Viewing facial expressions of pain engages cortical areas involved in the direct experience of pain

Recent neuroimaging and neuropsychological work has begun to shed light on how the brain responds to the viewing of facial expressions of emotion. However, one important category of facial expression that has not been studied on this level is the facial expression of pain. We investigated the neural response to pain expressions by performing functional magnetic resonance imaging (fMRI) as subjects viewed short video sequences showing faces expressing either moderate pain or, for comparison, no pain. In alternate blocks, the same subjects received both painful and non-painful thermal stimulation. Facial expressions of pain were found to engage cortical areas also engaged by the first-hand experience of pain, including anterior cingulate cortex and insula. The reported findings corroborate other work in which the neural response to witnessed pain has been examined from other perspectives. In addition, they lend support to the idea that common neural substrates are involved in representing one's own and others' affective states.

Investigating the phenomenological matrix of mindfulness-related practices from a neurocognitive perspective

There has been a great increase in literature concerned with the effects of a variety of mental training regimes that generally fall within what might be called contemplative practices, and a majority of these studies have focused on mindfulness. Mindfulness meditation practices can be conceptualized as a set of attention-based, regulatory, and self-inquiry training regimes cultivated for various ends, including wellbeing and psychological health. This article examines the construct of mindfulness in psychological research and reviews recent, nonclinical work in this area. Instead of proposing a single definition of mindfulness, we interpret it as a continuum of practices involving states and processes that can be mapped into a multidimensional phenomenological matrix which itself can be expressed in a neurocognitive framework. This phenomenological matrix of mindfulness is presented as a heuristic to guide formulation of next-generation research hypotheses from both cognitive/behavioral and neuroscientific perspectives. In relation to this framework, we review selected findings on mindfulness cultivated through practices in traditional and research settings, and we conclude by identifying significant gaps in the literature and outline new directions for research.

Minds "at attention": mindfulness training curbs attentional lapses in military cohorts

We investigated the impact of mindfulness training (MT) on attentional performance lapses associated with task-unrelated thought (i.e., mind wandering). Periods of persistent and intensive demands may compromise attention and increase off-task thinking. Here, we investigated if MT may mitigate these deleterious effects and promote cognitive resilience in military cohorts enduring a high-demand interval of predeployment training. To better understand which aspects of MT programs are most beneficial, three military cohorts were examined. Two of the three groups were provided MT. One group received an 8-hour, 8-week variant of Mindfulness-based Mind Fitness Training (MMFT) emphasizing engagement in training exercises (training-focused MT, n = 40), a second group received a didactic-focused variant emphasizing content regarding stress and resilience (didactic-focused MT, n = 40), and the third group served as a no-training control (NTC, n = 24). Sustained Attention to Response Task (SART) performance was indexed in all military groups and a no-training civilian group (CIV, n = 45) before (T1) and after (T2) the MT course period. Attentional performance (measured by A’, a sensitivity index) was lower in NTC vs. CIV at T2, suggesting that performance suffers after enduring a high-demand predeployment interval relative to a similar time period of civilian life. Yet, there were significantly fewer performance lapses in the military cohorts receiving MT relative to NTC, with training-focused MT outperforming didactic-focused MT at T2. From T1 to T2, A’ degraded in NTC and didactic-focused MT but remained stable in training-focused MT and CIV. In sum, while protracted periods of high-demand military training may increase attentional performance lapses, practice-focused MT programs akin to training-focused MT may bolster attentional performance more than didactic-focused programs. As such, training-focused MT programs should be further examined in cohorts experiencing protracted high-demand intervals.

The influence of memory load upon delay-interval activity in a working-memory task: an event-related functional MRI study

We conducted two fMRI studies to investigate the sensitivity of delay-period activity to changes in memory load during a delayed-recognition task for faces. In Experiment 1, each trial began with the presentation of a memory array consisting of one, two, or three faces that lasted for 3 sec. A 15-sec delay period followed during which no stimuli were present. The delay interval concluded with a one-face probe to which subjects made a button press response indicating whether this face was part of the memory array. Experiment 2 was similar in design except that the delay period was lengthened to 24 sec, and the memory array consisted of only one or three faces. We hypothesized that memory maintenance processes that spanned the delay interval would be revealed by their sensitivity to memory load. Long delay intervals were employed to temporally dissociate phasic activity engendered by the memory array from sustained activity reflecting maintenance. Regions of interest (ROIs) were defined anatomically for the superior frontal gyri (SFG), middle frontal gyri (MFG), and inferior frontal gyri (IFG), intraparietal sulci (IPS), and fusiform gyri (FFG) on a subject-by-subject basis. The mean time course of activity was determined for all voxels within these regions and for that subset of voxels within each ROI that correlated significantly with an empirically determined reference waveform. In both experiments, memory load significantly influenced activation 6--9 sec following the onset of the memory array with larger amplitude responses for higher load levels. Responses were greatest within MFG, IPS, and FFG. In both experiments, however, these load-sensitive differences declined over successive time intervals and were no longer significant at the end of the delay interval. Although insensitive to our load manipulation, sustained activation was present at the conclusion of the delay interval within MFG and other prefrontal regions. IPS delay activity returned to prestimulus baseline levels prior to the end of the delay period in Experiment 2, but not in Experiment 1. Within FFG, delay activity returned to prestimulus baseline levels prior to the conclusion of the delay interval in both experiments. Thus, while phasic processes engendered by the memory array were strongly affected by memory load, no evidence for load-sensitive delay-spanning maintenance processes was obtained.

What is inhibited in inhibition of return?

Research on temporal-order judgments, reference frames, discrimination tasks, and links to oculomotor control suggest important differences between inhibition of return (IOR) and attentional costs and benefits. Yet, it is generally assumed that IOR is an attentional effect even though there is little supporting evidence. The authors evaluated this assumption by examining how several factors that are known to influence attentional costs and benefits affect the magnitude of IOR: target modality, target intensity, and response mode. Results similar to those previously reported for attention were observed: IOR was greater for visual than for auditory targets, showed an inverse relationship with target intensity, and was equivalent for manual and saccadic responses. Important parallels between IOR and attentional costs and benefits are indicated, suggesting that, like attention, IOR may in part affect sensory-perceptual processes.

Promoting Novelty in Vision: Inhibition of Return Modulates Perceptual-Level Processing

To facilitate visual search of complex scenes, information arising from recently attended locations is subject to a selective inhibition in processing known as inhibition of return (IOR). Although the mechanisms of IOR remain unresolved, both motor and perceptual influences have been proposed based on reaction time (RT) studies. Here we report the results of two reflexive cuing studies in which signal detection methodology was employed to directly examine the effects of IOR on perception. IOR was found to be associated with a significant reduction in the accuracy of target discriminations at recently attended locations. Further, these effects of IOR on response accuracy were independent of whether emphasis was placed on the speed of responding. These results provide the first direct evidence that IOR can affect the perceptual quality of visual processing.

The role of prefrontal cortex in resolving distractor interference

We investigate the hypothesis that those subregions of the prefrontal cortex (PFC) found to support proactive interference resolution may also support delay-spanning distractor interference resolution. Ten subjects performed delayed-recognition tasks requiring working memory for faces or shoes during functional MRI scanning. During the 15-sec delay interval, task-irrelevant distractors were presented. These distractors were either all faces or all shoes and were thus either congruent or incongruent with the domain of items in the working memory task. Delayed-recognition performance was slower and less accurate during congruent than during incongruent trials. Our fMRI analyses revealed significant delay interval activity for face and shoe working memory tasks within both dorsal and ventral PFC. However, only ventral PFC activity was modulated by distractor category, with greater activity for congruent than for incongruent trials. Importantly, this congruency effect was only present for correct trials. In addition to PFC, activity within the fusiform face area was investigated. During face distraction, activity was greater for face relative to shoe working memory. As in ventrolateral PFC, this congruency effect was only present for correct trials. These results suggest that the ventrolateral PFC and fusiform face area may work together to support delay-spanning interference resolution.

Selective attention supports working memory maintenance by modulating perceptual processing of distractors

Selective attention has been shown to bias sensory processing in favor of relevant stimuli and against irrelevant or distracting stimuli in perceptual tasks. Increasing evidence suggests that selective attention plays an important role during working memory maintenance, possibly by biasing sensory processing in favor of to-be-remembered items. In the current study, we investigated whether selective attention may also support working memory by biasing processing against irrelevant and potentially distracting information. Event-related potentials (ERPs) were recorded while subjects (n = 22) performed a delayed-recognition task for faces and shoes. The delay period was filled with face or shoe distractors. Behavioral performance was impaired when distractors were congruent with the working memory domain (e.g., face distractor during working memory for faces) relative to when distractors were incongruent with the working memory domain (e.g., face distractor during shoe working memory). If attentional biasing against distractor processing is indeed functionally relevant in supporting working memory maintenance, perceptual processing of distractors is predicted to be attenuated when distractors are more behaviorally intrusive relative to when they are nonintrusive. As such, we predicted that perceptual processing of distracting faces, as measured by the face-sensitive N170 ERP component, would be reduced in the context of congruent (face) working memory relative to incongruent (shoe) working memory. The N170 elicited by distracting faces demonstrated reduced amplitude during congruent versus incongruent working memory. These results suggest that perceptual processing of distracting faces may be attenuated due to attentional biasing against sensory processing of distractors that are most behaviorally intrusive during working memory maintenance.

Tracking the time-course of attentional involvement in spatial working memory: an event-related potential investigation

Spatial working memory is a cognitive brain mechanism that enables the temporary maintenance and manipulation of spatial information. Recent neuroimaging and behavioral studies have led to the proposal that directed spatial attention is the mechanism by which location information is maintained in spatial working memory. Yet it is unclear whether attentional involvement is required throughout the period of active maintenance or is only invoked during discrete task-phases such as mnemonic encoding. In the current study, we aimed to track the time-course of attentional involvement during spatial working memory by recording event-related brain potentials (ERPs) from healthy volunteers. In Experiment 1, subjects performed a delayed-recognition task. Each trial began with the presentation of a brief stimulus (S1) that indicated the relevant location that subjects were to maintain in working memory. A 4.8-5.3 sec delay interval followed during which a single task-irrelevant probe was presented. The delay interval concluded with a test item (S2) to which subjects made a response indicating whether the S2-location was the same as the S1-memory location. To determine if attention was differentially engaged during discrete phases of the trial, task-irrelevant probes were presented early (400-800 msec following S1-offset) or late (2600-3000 msec following S1-offset) during the delay interval. Sensory-evoked ERPs (P1 and N1) elicited by these irrelevant probes showed attention-like modulations with greater amplitude responses for probes occurring at the S1-memory locations in comparison to probes presented at other locations. This pattern was obtained for both early- and late-delay probes. Probe-evoked activity during delayed-recognition trials was similar to activity observed when spatial attention was explicitly focused on a location in visual space (Experiment 2). These results are consistent with a model of spatial working memory in which perceptual level selective attention is utilized throughout the entire period of active maintenance to keep relevant spatial information in mind.

Taming a wandering attention: short-form mindfulness training in student cohorts

Mindfulness training (MT) is a form of mental training in which individuals engage in exercises to cultivate an attentive, present centered, and non-reactive mental mode. The present study examines the putative benefits of MT in University students for whom mind wandering can interfere with learning and academic success. We tested the hypothesis that short-form MT (7 h over 7 weeks) contextualized for the challenges and concerns of University students may reduce mind wandering and improve working memory. Performance on the sustained attention to response task (SART) and two working memory tasks (operation span, delayed-recognition with distracters) was indexed in participants assigned to a waitlist control group or the MT course. Results demonstrated MT-related benefits in SART performance. Relative to the control group, MT participants had higher task accuracy and self-reported being more “on-task” after the 7-week training period. MT did not significantly benefit the operation span task or accuracy on the delayed-recognition task. Together these results suggest that while short-form MT did not bolster working memory task performance, it may help curb mind wandering and should, therefore, be further investigated for its use in academic contexts.

Mindfulness training improves attentional task performance in incarcerated youth: a group randomized controlled intervention trial

We investigated the impact of cognitive behavioral therapy and mindfulness training (CBT/MT) on attentional task performance in incarcerated adolescents. Attention is a cognitive system necessary for managing cognitive demands and regulating emotions. Yet persistent and intensive demands, such as those experienced during high-stress intervals like incarceration and the events leading to incarceration, may deplete attention resulting in cognitive failures, emotional disturbances, and impulsive behavior. We hypothesized that CBT/MT may mitigate these deleterious effects of high stress and protect against degradation in attention over the high-stress interval of incarceration. Using a quasi-experimental, group randomized controlled trial design, we randomly assigned dormitories of incarcerated youth, ages 16-18, to a CBT/MT intervention (youth n = 147) or an active control intervention (youth n = 117). Both arms received approximately 750 min of intervention in a small-group setting over a 3-5 week period. Youth in the CBT/MT arm also logged the amount of out-of-session time spent practicing MT exercises. The Attention Network Test was used to index attentional task performance at baseline and 4 months post-baseline. Overall, task performance degraded over time in all participants. The magnitude of performance degradation was significantly less in the CBT/MT vs. control arm. Further, within the CBT/MT arm, performance degraded over time in those with no outside-of-class practice time, but remained stable over time in those who practiced mindfulness exercises outside of the session meetings. Thus, these findings suggest that sufficient CBT/MT practice may protect against functional attentional impairments associated with high-stress intervals.

Does mindfulness training help working memory 'work' better?

There has been a proliferation of mindfulness training (MT) programs offered across a multitude of settings, including military, business, sports, education, and medicine. As such, ascertaining training effectiveness and determining best practices for program delivery are of the utmost importance. MT is often introduced to promote an array of desired effects from better mood, better leadership and management skills, to improved workplace or academic performance. Despite the diversity of factors motivating adoption of MTs, it can be argued from a cognitive training perspective that there should be uniformity in the core cognitive processes strengthened via repeated and systematic engagement in MT exercises. Herein, we explore the hypothesis that MT promotes salutary changes in the brain's working memory (WM) system. We review prior research and highlight aspects of MT programs that may be critical for achieving beneficial WM effects. Further, we suggest that given the centrality of WM in core processes such as emotion regulation, problem solving, and learning, MT programs capable of achieving WM benefits may be best positioned to promote other desired outcomes (e.g. reductions in negative mood). For these reasons, we recommend that more studies include WM metrics in their evaluation of MT programs.

Attention to faces modulates early face processing during low but not high face discriminability

In the present study, we investigated whether attention to faces results in sensory gain modulation. Participants were cued to attend either to faces or to scenes in superimposed face-scene images for which face discriminability was manipulated parametrically. The face-sensitive N170 event-related potential component was used as a measure of early face processing. Attention to faces modulated N170 amplitude, but only when faces were not highly discriminable. Additionally, directing attention to faces modulated later processing (~230-300 msec) for all discriminability levels. These results demonstrate that attention to faces can modulate perceptual processing of faces at multiple stages of processing, including early sensory levels. Critically, the early attentional benefit is present only when the "face signal" (i.e., the perceptual quality of the face) in the environment is suboptimal.

Dynamic brain network configurations during rest and an attention task with frequent occurrence of mind wandering

Mind wandering (MW) has become a prominent topic of neuroscientific investigation due to the importance of understanding attentional processes in our day-to-day experiences. Emerging evidence suggests a critical role for three large-scale brain networks in MW: the default network (DN), the central executive network (CEN), and the salience network (SN). Advances in analytical methods for neuroimaging data (i.e., dynamic functional connectivity, DFC) demonstrate that the interactions between these networks are not static but dynamically fluctuate over time (Chang & Glover, 2010, NeuroImage, 50(1), 81-98). While the bulk of the evidence comes from studies involving resting-state functional MRI, a few studies have investigated DFC during a task. Direct comparison of DFC during rest and task with frequent MW is scarce. The present study applies the DFC method to neuroimaging data collected from 30 participants who completed a resting-state run followed by two runs of sustained attention to response task (SART) with embedded probes indicating a high prevalence of MW. The analysis identified five DFC states. Differences between rest and task were noted in the frequency of three DFC states. One DFC state characterized by negative DN-CEN/SN connectivity along with positive CEN-SN connectivity was more frequently observed during task vs. rest. Two DFC states, one of which was characterized by weaker connectivity between networks, were more frequently observed during rest than task. These findings suggest that the dynamic relationships between brain networks may vary as a function of whether ongoing cognitive activity unfolds in an "unconstrained" manner during rest or is "constrained" by task demands.

The influence of concentrative meditation training on the development of attention networks during early adolescence

We investigate if concentrative meditation training (CMT) offered during adolescent development benefits subsystems of attention using a quasi-experimental design. Attentional alerting, orienting, and conflict monitoring were examined using the Attention Network Test (ANT) in 13-15 year old children who received CMT as part of their school curriculum (CMT group: N = 79) vs. those who received no such training (control group: N = 76). Alerting and conflict monitoring, but not orienting, differed between the CMT and control group. Only conflict monitoring demonstrated age-related improvements, with smaller conflict effect scores in older vs. younger participants. The influence of CMT on this system was similar to the influence of developmental maturity, with smaller conflict effects in the CMT vs. control group. To examine if CMT might also bolster conflict-triggered upregulation of attentional control, conflict effects were evaluated as a function of previous trial conflict demands (high conflict vs. low conflict). Smaller current-trial conflict effects were observed when previous conflict was high vs. low, suggesting that similar to adults, when previous conflict was high (vs. low) children in this age-range proactively upregulated control so that subsequent trial performance was benefitted. The magnitude of conflict-triggered control upregulation was not bolstered by CMT but CMT did have an effect for current incongruent trials preceded by congruent trials. Thus, CMT's influence on attention may be tractable and specific; it may bolster attentional alerting, conflict monitoring and reactive control, but does not appear to improve orienting.

Is resilience trainable? An initial study comparing mindfulness and relaxation training in firefighters

Motivated by the growing interest in promoting resilience in first responders and other professionals who face threatening professional circumstances, the current study investigated the effectiveness of offering a short-form mindfulness training (MT) program to firefighters. The overarching question was to determine if psychological and cognitive markers of resilience are bolstered via MT. Firefighters (n = 121) were assigned to an MT program (n = 42), an active-comparison relaxation training program (RT, n = 31), or served as no-training controls (NTC, n = 48). Both the MT and RT programs were contextualized for firefighters and consisted of 4, 2-h training sessions delivered over 4 weeks by the same expert trainer, as well as 10-15 min of daily out-of-class practice. Intent-to-treat analyses revealed a significantly greater increase in psychological resilience from baseline (T1) to post-training (T2) in firefighters who received MT vs. RT or no training. In addition, positive affect and objective attentional task performance demonstrated a greater increase over time (from T1 to T2) with more days per week of out-of-class practice for the MT group but not for the RT group. These results suggest that MT moreso than RT bolsters markers of resilience in firefighters.

Fractionating the role of executive control in control over worry: a preliminary investigation

Uncontrollable anxious thought characterizes a number of emotional disorders. Little is known, however, about the cognitive mechanisms that underlie the ability to control these thoughts. The present study investigated the extent to which two well-characterized executive control processes--working memory and inhibition--are engaged when an individual attempts to control worry. Participants completed a concurrent assessment of these processes while attempting to control personally-relevant worried and neutral thoughts. To examine the specificity of these effects to attempts to control worry, versus a residual "depletion" effect of having previously engaged in worry, a subset of participants completed the assessment without instructions to control their worried or neutral thoughts. Attempts to control worry engaged working memory and inhibition to a greater extent than did attempts to control neutral thought. This increased engagement was not explained solely by anxious affect, nor was it significantly associated with trait worry. Engagement did not differ by group, suggesting that executive control depletion by worry cannot be dismissed as an alternative explanation of these findings. These results highlight working memory and inhibition as potentially valuable constructs for deepening our understanding of the nature and treatment of worry and its control.

Temporal characteristics of top-down modulations during working memory maintenance: an event-related potential study of the N170 component

We investigated the top-down influence of working memory (WM) maintenance on feedforward perceptual processing within occipito-temporal face processing structures. During event-related potential (ERP) recordings, subjects performed a delayed-recognition task requiring WM maintenance of faces or houses. The face-sensitive N170 component elicited by delay-spanning task-irrelevant grayscale noise probes was examined. If early feedforward perceptual activity is biased by maintenance requirements, the N170 ERP component elicited by probes should have a greater N170 amplitude response during face relative to house WM trials. Consistent with this prediction, N170 elicited by probes presented at the beginning, middle, and end of the delay interval was greater in amplitude during face relative to house WM. Thus, these results suggest that WM maintenance demands may modulate early feedforward perceptual processing for the entirety of the delay duration. We argue based on these results that temporally early biasing of domain-specific perceptual processing may be a critical mechanism by which WM maintenance is achieved.

Mindfulness training as cognitive training in high-demand cohorts: An initial study in elite military servicemembers

Cognitive ability is a key selection criterion for entry into many elite professions. Herein, we investigate whether mindfulness training (MT) can enhance cognitive performance in elite military forces. The cognitive effects of a short-form 8-h MT program contextualized for military cohorts, referred to as Mindfulness-Based Attention Training (MBAT), were assessed. Servicemembers received either a 2-week (n=40) or 4-week (n=36) version of MBAT or no training (NTC, n=44). Sustained attention and working memory task performance along with self-reported cognitive failures were assessed at study onset (T1) and 8-weeks later (T2). In contrast to both the NTC and 2-week MT groups, the 4-week MT group significantly improved over time on attention and working memory outcome measures. Among the 4-week more so than the 2-week MBAT participants, working memory performance improvements were correlated with their amount of out-of-class MT practice. In addition to these group-wise effects, all participants receiving MBAT decreased in their self-reported cognitive failures from T1 to T2. Importantly, none of these improvements were related to self-reported task motivation. Together, these results suggest that short-form MT, when delivered over a 4-week delivery schedule, may be an effective cognitive training tool in elite military cohorts.

Self-reported Mind Wandering and Response Time Variability Differentiate Prestimulus Electroencephalogram Microstate Dynamics during a Sustained Attention Task

Brain activity continuously and spontaneously fluctuates during tasks of sustained attention. This spontaneous activity reflects the intrinsic dynamics of neurocognitive networks, which have been suggested to differentiate moments of externally directed task focus from episodes of mind wandering. However, the contribution of specific electrophysiological brain states and their millisecond dynamics to the experience of mind wandering is still unclear. In this study, we investigated the association between electroencephalogram microstate temporal dynamics and self-reported mind wandering. Thirty-six participants completed a sustained attention to response task in which they were asked to respond to frequently occurring upright faces (nontargets) and withhold responses to rare inverted faces (targets). Intermittently, experience sampling probes assessed whether participants were focused on the task or whether they were mind wandering (i.e., off-task). Broadband electroencephalography was recorded and segmented into a time series of brain electric microstates based on data-driven clustering of topographic voltage patterns. The strength, prevalence, and rate of occurrence of specific microstates differentiated on- versus off-task moments in the prestimulus epochs of trials preceding probes. Similar associations were also evident between microstates and variability in response times. Together, these findings demonstrate that distinct microstates and their millisecond dynamics are sensitive to the experience of mind wandering.

Associations between self-reported spontaneous thought and temporal sequences of EEG microstates

Thought dynamically evolves from one moment to the next even in the absence of external stimulation. The extent to which patterns of spontaneous thought covary with time-varying fluctuations in intrinsic brain activity is of great interest but remains unknown. We conducted novel analyses of data originally reported by Portnova et al. (2019) to examine associations between the intrinsic dynamics of EEG microstates and self-reported thought measured using the Amsterdam Resting-State Questionnaire (ARSQ). Accordingly, the millisecond fluctuations of microstates were associated with specific dimensions of thought. We evaluated the reliability of these findings by combining our results with those of another study using meta-analysis. Importantly, we extended this investigation using multivariate methods to evaluate multidimensional thought profiles of individuals and their links to sequences of successive microstates. Thought profiles were identified based on hierarchical clustering of ARSQ ratings and were distinguished in terms of the temporal ordering of successive microstates based on sequence analytic methods. These findings demonstrate the relevance of assessing spontaneous thought for understanding intrinsic brain activity and the novel use of sequence analysis for characterizing microstate dynamics. Integrating the phenomenological view from within remains crucial for understanding the functional significance of intrinsic large-scale neurodynamics.